I've heard that some jurisdictions are planning on eliminating, if not allowing citizens to revise, the sex field on documents like passports and drivers licenses. I'm just wondering why it's listed in the first place and whether there are any actual reasons for why they should continue to be listed.

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    My id does not have a sex field. Neither does my driver's license and that document is from the last millenium.
    – Roland
    Commented Feb 3, 2023 at 6:44
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    "actual reasons" That is probably the most interesting part. What is an actual reason? Something that helps somebody in some way maybe? Then the sex info is for example really nice for choosing the title when addressing a person. Would that be sufficient for an actual reason? Commented Feb 3, 2023 at 8:37
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    Side note which might be of interest: the British driving licence doesn't have an explicit sex marker, but does have an implicit one: the date of birth in the driver number is encoded differently for male and female, where the months run from 01 to 12 for male and 51 to 62 for female. Commented Feb 3, 2023 at 11:48
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    @Roland My US passport and my Texas driver's license both specify my gender. Your country may vary. The answer to the question likely involves law enforcement (eyewitness observations of criminal activities oftentimes involve a gender identification) and social inertia (the card has always contained that information; why change it?) Commented Feb 3, 2023 at 15:47
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    @Roland Really? Because in my case my ID is about the only thing about me that gets to have sex :P
    – dsollen
    Commented Feb 3, 2023 at 17:50

9 Answers 9


There is no absolute reason why sex has to be listed on an identity document.

The fields that are sometimes found on identity documents are those that most people can easily give, don't frequently change and differ from person to person.

So most (not all) people are assigned a name at, or close to birth. The date of birth is known for most (not all) people. Most (not all) people have little difficulty answering the question "What's your name and birth date?" And likewise, the sex of most (not all) people is easily assigned at or near birth and most (not all) people have little difficulty answering the question "Male or Female?".

Moreover, these three pieces of information change only once or twice in their life, if at all, for most people.

It is hard to think of other qualities that have these three properties of universality and fixedness that the classic Name, Sex, DoB have.

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    Nit picking here and not a downvote, but my wife's name changed when she married me, we've got a friend who's on her third husband and fourth surname. Also, gendered names are often culturally specific and not always recognisable to people with a different heritage. Commented Feb 3, 2023 at 12:20
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    @DaveGremlin true name changes often, but it's also the best way to uniquly identify someone. You don't ask "are you male with dob X and mother maiden name of Y?" You say "are you jane doe?" It's inconvenient that names change regularly, but name is still one of the best identifiers, and the way most people distinguish others, so were sort of stuck with that on an ID card.
    – dsollen
    Commented Feb 3, 2023 at 17:19
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    @tim: My driver's license does have my eye color and height on it.
    – dan04
    Commented Feb 3, 2023 at 17:56
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    Name changes at least once for at least 40% of people. Eye color is probably more reliable than name, though a small percentage of people do change eye colors (colored lenses). It's pretty easy to lie about name, sex and DOB. Part of why ID cards have traits on them is so one could try to believe that you are the person on the ID card so some of the traits should be identifiable and hard do fake.
    – Ram
    Commented Feb 3, 2023 at 21:44
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    @Ram "Name changes at least once for at least 40% of people" you forgot to add "in some countries".
    – Jan
    Commented Feb 5, 2023 at 10:04

Having the "sex" information on the ID card might help identify identity theft. That would hold true especially when the name is ambiguous or uni-sex. Some examples:

  • Karl Maria (von Weber) - German name

  • Jean-Marie - French first name for a man

  • Marie-Jean - French name for girl (if I am not mistaken)

  • Eddie - unisex name (diminutive) in English

  • Sasha - diminutive of Alexander, Alexandra, Aleksey...

Now if you would see a major discrepancy between the person and the info on the card, you would be more likely to be cautious about dealing with that person. Equally useful for police and any other authority.

Maybe less relevant, but still possible occasionally, parents are quite creative when choosing their baby's names. Example: in the movie "Stargate Atlantis", Rodney's full name is "Meredith Rodney McKay". If you would not see the person, would you know their "sex"?

I had a colleague in school (a long time ago), and before we saw "them", we knew their name + first name (without knowing which is which). We could not decide if we would have a new girl colleague or a new male colleague. Everything was clarified when HE presented HIMelf for the classes. The family name was typical for a girl's name, and the first name was typical for a man's. So for cases like this, the information of "sex" can be very helpful.

I have a typical male's name in my country. However, when dealing with people from other countries / cultures, just looking at my name they expected to meet a girl. In one of the situations, I was even assigned a sleeping place in a girl's room - and that was fixed quickly when they saw me the first time.

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    "Karl Maria" is a male name. It's not ambiguous or uni-sex.
    – Roland
    Commented Feb 3, 2023 at 7:03
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    Yes, for someone familiar with that cultural peculiarity. In other countries / cultures, Maria is strictly a girl's name. Even in Germany, men are not named just Maria, I guess.
    – virolino
    Commented Feb 3, 2023 at 7:09
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    @Roland, "Karl Maria" is such a male name that an exception had to be made in German registry laws, which usually require a first name to be appropriate to the sex. With this exception for devout Catholic parents.
    – o.m.
    Commented Feb 3, 2023 at 7:19
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    "I tell ya, life ain’t easy for a boy named “Sue”" Commented Feb 3, 2023 at 17:16
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    If your process to stop identity theft relies on verifying the match up between name and apparent gender then you have a pretty darn fragile process. And one that fails as soon as the perps line up their representative's gender w claimed gender. Commented Feb 3, 2023 at 18:46

Honestly I feel the real answer is human nature and inertia.

There are existing answers about sex being used as a static distinguishing value and that it might help with identity theft already, but I feel they are more post-hoc justifications more then the real motivation behind the decision, as demonstrated by all the potential counter arguments to those justifications. There are other potential better unique identifiers, and plenty of people don't look like their sex so you face plenty of 'false positives' if you are trying to identify someone by guessing if they match sex.

The true answer is long ago someone picked sex as an identifier because humans are use to using sex that way and now were just stuck going along with it. Back when we started using sex as an identifier most people weren't aware of gender/sex distinction of that non binary sexes existed. I suppose you could say it seemed like a good idea at the time.

And now everyone is using it. We've written programs that expect sex to exist to distinguish between people. Plenty of code has foolishly hard coded expectations of human nature around sex even, I have seen code that presumed only a female's last name would change before! It's habit to use sex this way, in fact it's more then habit, it feels 'right' to most people.

The fact of the mater is we naturally think of sex as a logical division of people; We've been doing that since before ID cards or even written language existed. It's a (seemingly...) easy thing to define and use, it feels 'right', and while there are some legitimate situations where its less then ideal they tend to be the minority case. Most people just want to stick with what worked in the past and they are use to.

An idealized system might use some other identifiers that better distinguish you as a person, maybe some UUID that can be publicly used - there are issues with public UUID and how their usually used/abused, I could think of ways to mitigate them, but lets not go down that rabbit hole right now. The point is a better system could be imagined, the problem is that convincing people to switch to it, to stop doing what they are use to and fight inertia, all to fix an issue that only affects a small minority of those using the ID is hard.

To give an analogy the USA would have a much easier time if they used the metric system everywhere rather then our completely random "how many inches are in a mile again?" system of measurement. However, the expense and difficulty of converting to a metric system now that everyone is use to our current system is just so high we likely will never switch, even if it theoretically would be better if we used a metric system.

In the same way your just not going to convince people to not use sex as a distinguisher regardless of it's possible negatives. It's just what everyone knows and takes for granted 'should' be on an ID card.

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    I think it is an important point that systems are setup to require it for various reasons and it is just difficult to get the systems updated to change that.
    – Joe W
    Commented Feb 3, 2023 at 17:43
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    Also linguistics. In some languages, all nouns, adjectives, and/or verbs indicate the gender of their referent, so it's hard to make a grammatically correct sentence to or about a person without categorizing them as male or female.
    – dan04
    Commented Feb 3, 2023 at 18:06
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    Agree w inertia. We're debating this subject now as societies. We weren't when formalized ID systems were set up. Maybe we'll keep gender/sex on IDs in the future, maybe we won't, but the reason we have them right now is because that's the way it was done before. Commented Feb 3, 2023 at 18:49

The purpose of most identification cards is to have a readily available and easy to use means to know who someone is from a legal perspective. As such there are a few hard requirements:

  1. The person's identity - typically this is a name but there are many John Smith's so that's not enough, typically date of birth is included as well to minimize duplications though that does not suffice either.
  2. The legal jurisdiction in question - ie is this identity defined according to and in Australia or Texas or The USA?
  3. Physical traits that could be used to relate the person claiming to be identified the card with the identity named in the card.

The first two are straight forward enough, the topic you'r querying seems to lie is in the third area. Some physical traits are readily changed - hair length, while others are very difficult to meaningfully change - height. Some traits where once considered very difficult to change but now are readily changed - eg eye color.

You asked specifically about sex. Sex is often identifiable quickly and while this has never been universally true, in the time since driver's licenses and passports were first created it has been largely true. As an counter example, I'm a cis-male but in some photos of me when I was a teenager you might guess I'm female. As such, much like eye color, sex is a pretty good trait for recognizing someone but is not very reliable and is currently a social hot topic.

The more physical traits you list on an identity card, the more reliable a connection can be made.

Some traits like finger prints, retina patterns, and hand geometry are exceedingly difficult to fake and as such are included directly or indirectly on higher security identification systems such as the Global Entry trusted traveller program.


It is (generally) a visibly identifiable characteristic that helps to identify a person.

Before I continue, yes, I recognize this is not 100% accurate, some people are androgenous, some people take efforts to look like members of the opposite sex (whether because they are transgender or simply because they feel like it), etc. It is not 100% perfect, but neither is any other identifying characteristic on your ID card; you can always dye your hair, wear color contacts, gain/lose weight, change your address, change your signature, etc. Nothing on your ID card is 100% guaranteed accurate all the time, but your "identifying characteristics" are things which, taken together, should largely remain verifiable and unchanged, with high probability.

Consider, for a moment, "white, woman, blonde hair, mid-30s". That paints a picture in your mind. If I showed you a picture of, say, Al Pacino, you could pretty readily tell me that this person does not match that description. Even if I showed you a picture of Leonardo DiCaprio, as he appeared in the movie Titanic, you could assess that this is probably not the right person. Now, it's certainly possible that picture of Leonardo is a woman with short hair and "manly" facial features, but it would at least raise a suspicion in your mind, and that's intentional, by design. If a legal officer (police, social services, what have you) sees someone who looks like Leonardo DiCaprio who is supposed to be a female, that person should be suspicious that this person may be committing identity fraud, even if it turns out to be a case of androgenity (is that a word?) in the end.

As a caveat, in order to accept the above explanation, you have to accept the premise that identity theft (and other forms of theft as well; for example, in the case of a driver's license, the police can cross-reference the owner of a vehicle against the person driving it to detect cases of Grand Theft Auto) is a larger problem than someone who is androgenous or cross-gender (I don't know the actual term for this; I mean someone who, for any reason, wants to look like the opposite gender, including but not limited to trans people) being "unduly questioned" due to not appearing as their identification says they should. The latter issue is attempted to be alleviated by also having a photo on the identification record but is also imperfect, for much the same reasons. If you do not accept that premise, then this answer is not going to be acceptable to you, and that's ok.


I'm just wondering why it's listed in the first place

Tradition. Documents bound to a person's identity originally did not have photographs, fingerprints, etc. Instead, they bore a written description of the person including physical characteristics such as height, weight, eye color, hair color, shape of face, "distinguishing marks" (scars, moles, that sort of thing) and, indeed, sex (as it was called in those days). Not every document had all of these, of course. As photographs became more common and eventually ubiquitous, many of these items have fallen by the wayside, and different jurisdictions and different authorities have dropped different items at different times.

  • My ID card still lists eye color and height and last time I applied for a new one they even checked the eye color (by eye). Commented Feb 5, 2023 at 15:21

Military service.

There are histories when foreigners that recently acquired a citizenship in Russia have been mobilized to fight in the ongoing war. Some of these were women, but the name and family name were such that this has not been immediately seen. This explains why the government needs to know the gender of the citizen, and if some database simply contains all information that is in the passport, makes sense to include it as well.

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    I don't buy this one. Yes sex can be used for the draft, but sex will be known in records regardless of identity card. It doesn't have to be on the id card just for the draft.
    – dsollen
    Commented Feb 3, 2023 at 17:15
  • It should be normally easy to tell between man and woman in the draft office, but if not in some more complicated cases, or the officer abuses his rights for fun, kind of convenient just to show the passport. Looks like they used some kind of database without the gender information.
    – Stančikas
    Commented Feb 3, 2023 at 17:23

My US passport and my Texas driver's license both specify my gender / sex (the terms are interchangeable so long as the choices are male or female, and nothing else). Other people's country may vary.

The answer to the question involves law enforcement as eyewitness observations of criminal activities oftentimes involve a gender identification (even if incorrect), and social / bureaucratic inertia as the card has always contained that information; so why change it? And finally, there's religion. Multiple religious organizations say men are men and women are women; there is no crossover (even though there is).

Eyewitness reports while oftentimes dubious, occasionally are helpful. In the cases where gender is consistently reported, that the suspect is consistently identified as male or female can aid in law enforcement investigations. Law enforcement is strongly against removing that information from ID cards.

This might just be bureaucratic inertia. The information has always been there in jurisdictions that report gender on some sort of ID card. Changing bureaucratic inertia is non-trivial due in part to "that's how it has always been" attitudes.

Finally, in many countries there is a religion-based backlash against removing such information. The US is a good example, but there are many other examples. Various political organizations explicitly ignore the huge amount of scientific research that indicates that gender identity is not as solid as people think. Per these organizations, men are men and are necessarily attracted to women, while women are women and are necessarily attracted to men. Any in-betweens are religiously forbidden by the advocates of this very strong split, scientific research be damned.

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    The question asked about sex, but you're using the word "gender". Are the words interchangeable?
    – Jedediah
    Commented Feb 4, 2023 at 22:52
  • @Jedediah The terms are interchangeable, so long as gender is either male or female, which it is with those IDs. Commented Feb 5, 2023 at 0:25

Sex has tended to be regarded as one of the fundamental overt attributes of the person.

It's inclusion on identity documents like passports - or what have become ersatz identity documents like driver's licences - is for similar reasons that age or (especially nowadays) photographs are included, namely to help verify on the spot the correspondence between the document and the bearer.

The sex correspondence can usually be assessed through voice characteristics, body size, their general bearing and manner, and so on.

Obviously, in terms of "passing off" or inappropriate use of someone else's identity document, having the sex indication alone on the document excludes about 50% of potential donors (including, traditionally, the person's marriage partner). An age indication excludes perhaps even more than 50%.

It is not always the determined fraudster planning ahead who needs to be deterred, but the person who might casually and impulsively offer a false document if there were no barrier at all - such as a son using his father's driving licence (if no age were recorded), or a wife using her husband's driving licence (if his name alone were sufficiently ambiguous as to sex).

  • Basically a fingerprint would be enough as ID but we don't have enough fingerprint scanners yet. Commented Feb 5, 2023 at 15:20
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    @Trilarion, there's never really one silver bullet with these things. Fingerprints do wear off, are altered by injury, and can be forged. Also, unless you carry a magnifying glass, Sherlock Holmes style, then comparing the finger with the print on the document could be problematic. Machinery that can read fingerprints and compare to a central computer database, requires trustworthy infrastructure, and a computerised database itself potentially becomes a valuable target for criminality.
    – Steve
    Commented Feb 5, 2023 at 16:07

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